Air-cooled muffler



J. S. FLUOR JR., ET AL 1am-000mm MUFFLER 2 Sheets-Sheet l Filed May 4,-195s my j.

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' J. S. FLUOR, JR.. ET AL AIR- COOLED MUFFLER Filed May 4, 1956 2Sheets-Sheet 2 to A Patented June 21, 1938 AIR-COOLED MUFFLER John S.Fluor, Jr., and Park W. Ash, Santa Ana, Calif., assignors to The FluorCorporation Ltd., Los Angeles, Calif., a corporation of CaliforniaApplication May 4, 1936, Serial No. 77,820

5 Claims.

This invention has to do with air cooled mufers for stationary engines,and relates particularly to improvements in muffler units wherein themuffler proper is mounted within a shell or stack through which thecooled air is drawn by the exhaust gas discharged from the muffler.

Our major purposes are to avoid overheating the mulller enclosing shell,and to improve upon the usual muffler installation of this type byaccomplishing greater cooling of both the muffler and the exhaust gases.The invention is parn ticularly adapted to that type of air cooledmuffler wherein air is drawn into a conduit surrounding both the exhaustpipe and muffler (the conduit including the above mentioned mufflersurrounding shell) from a pipe forming an air space about that portionof the exhaust pipe that is jacketed by the conduit. Air cooled muliflerunits of that type are described in Patent No. 1,966,620 issued to JohnS. Fluor, Jr., July 17, 1934, on Muffler, which discloses a systemwherein `air is taken into the outer pipe from the atmosphere outsidethe engine room, and is drawn into the inlet end `of the exhaust pipeand mufer surrounding conduit at a point within the engine room.

It has been found that in some installations, by the time the coolingair reaches the passage surrounding the muffler, the air has becomeheated to such a degree that it overheats the shell or stack surroundingthe muliler, and consequently causes the metal to oxidize anddeteriorate rapidly because of the impossibility of coating it with apaint that will withstand the high temperatures. In accordance with theinvention, we overcome this diiculty and protect the muffler stack, byjacketing the latter with anouter shell which provides a passage throughwhich air is drawn along the outer surface of the rstack, and thenceinto the air passage between the mulller and the stack. By virtue ofthis arrangement, i. e. the provision of two concentric air passagesabout the muffler, we avoidoverheating either cf the outer shells, andmaintain the outermost shell at a sufficiently low temperature that aheatresistant paint may be kept on it to prevent rusting and maintain agood appearance.

For the purpose of describing our invention, we have shown in theaccompanying drawings a typical stationary engine air cooled mulllerunit in which the exhaust pipe extends from within the engine room toconnect with a vertically positioned muffler at the outside, both themuffler and exhaust pipe being jacketed so that the (Cl. Gil-31) coolingair is drawn from the outside atmosphere into the room through an outercooling jacket, and thence through the inner jacket in Contact with theexhaust pipe and mufller. In the detailed description to follow,reference is had to the accompanying drawings, in which:

Fig. 1 is a general View showing the double air jackets about theexhaust pipe and muler;

Fig. 2 is an enlarged view showing the muffler and the surroundingshells, in vertical section; 10

Fig. 3 is an enlarged plan View on line 3-3 of Fig. 2; and

Fig. 4 is a fragmentary section on line 4-4 of Fig. 3, showing one ofthe muffler suspensions in detail.

In the typical form of muffler, installation shown in Fig. l, theexhaust pipe IU which connects at II with the diagrammaticallyillustrated 'engine I2 within room I3, extends downwardly through theoor I4 and then horizontally withc* in trench I5 tol the outside of theroom. The 0 outer end of the exhaust pipe connects at I6, see Fig. 2,into the side of the vertically extending muffler I'I, which, as will beunderstood, may be of any suitable type and construction. Typically, itis shown to comprise a cylindric shell I8 having top and bottom closuresI9 and 28, an outlet pipe 2|, and a series of baille elements 22, thedetails of which need not be described since they comprise no part ofthe invention.

The muffler I'l is enclosed by a cylindric stack 23 concentric with andspaced annularly about shell I8 to provide a passage 24 for the mufflercooling air. The bottom of shell 23 is welded or otherwise secured to abase plate 24a which is 35 fastened to the foundation 25 by anchor bolts26. The upper end of the stack supports a hood 21 comprising an outletpipe 28 and a downwardly flaring portion 29 welded at 3D to shell 23.The exhaust pipe IIJ is jacketed by a pipe 3l having 40 an open inletend 3.2 and an outlet end connecting -at 33 with the muffler surroundingshell 23. It may be observed at this point that by virtue of the upwarddischarge of combustion gases from the mufiler outlet EI into thetapered 45 throat formed by portion 29 of the hood, there is created anupward draft acting to draw air in the directions indicated by thearrows, into the inlet end 32 of pipe 3|, through passage 35 along theexhaust pipe, and thence upwardly through the annular passage 24surrounding the muffler. The air is :finally discharged, together withthe exhaust gases, through the stack outlet pipe 28.

The muffler I'I may be mounted within the `stack in any suitable manner,although we prefy55 erably employ a type of mounting that will permitthe muffler to shift horizontally in response to longitudinalcontraction or expansion of the exhaust pipe, occurring as a result ofits temperature changes. Typically, we have shown the muffler to bemounted on a two point suspension of the type constituting the subjectmatter of our Patent No. 2,110,395, issued March 8, 1938, on Air-cooledmuffler. As illustrated in Fig. 3 the individual suspensions, generallyindicated at 36, are located at diametrically opposite sides of themufller shell, and in a plane normal to the direction of expansion andcontraction of the exhaust pipe. Referring now to Figs. 3 and 4, each ofthe suspensions comprises a vertically extending bolt 31 carried by anarm member 38 welded at 39 and 4U to the muffler outlet 2l and shell i8,and secured to the upper end closure 4l of the muffler by bolt 42. Themuffler is vertically supported on a coil spring 43 placed about thelower end of bolt 31 and resting on bracket 44 mounted on shell 23 andhaving a top flared surface 45 along which spring 43 shifts as themuffler is shifted within the stack by expansion or contraction of theexhaust pipe. Spring 46 placed about the upper end of bolt 31 andbearing against a bracket 41 attached at 48 to the stack shell, imposesa yielding and vibration dainpening resistance to upward movement of themuffler.

Lateral movement of the muffler within the shell in a directiontransverse of its direction of movement in line with the exhaust pipe,is yieldably resisted by a coil spring 49 carried on bolt 50 and bearingagainst the outer surface 55a of bracket 41. As shown in Fig. 3, surface50a extends parallel with the direction of expansion and contraction ofthe exhaust pipe, and consequently serves as a guide for spring 49 sothat the muffler is confined to a straight path of travel in itsshifting movement.

Referring now to Fig. 2, the stack shell 23 is surrounded by an outershell 5I supported on the base plate 24a and spaced at its upper endfrom the hood 29 to permit air to be drawn, as indicated by the arrows,into the annular passage 52. The lower end of the hood is supported onthis outer shell 5I by brackets 53. Pipe 3| surrounding the exhaust pipeI0, is jacketed by an outer pipe 54 connecting at 55 into the side ofshell 5I. The opposite end 54a of pipe 54 extends upwardly about theinlet end 32 of pipe 3l and is closed by a plate 55 clamped betweenflanges 55 on the exhaust pipe. Thus it will be seen that shell 5l andpipe 54 provide an outer air jacket or conduit about the inner airconduit (shell 23 and pipe 3l), and that both the muffler and theexhaust pipe are double-jacketed to substantially the muffler outlet.

In operation, the upward draft of air in passage 24 created by theexhaust gas discharge from muiller outlet 2f, causes cool air from theatmosphere to be drawn through space 58 between the hood and shell 5l,into passage 52, and then through passage 59 within the outer exhaustpipe jacket 54, into the inlet end 32 of pipe 3l. From that point, andas previously explained, the air is drawn through passages 35 and 24 indirect contact with the exhaust pipe and muffler, and is finallydischarged with the combustion gases through the outlet pipe 28.

The downward circulation of air through the annular passage 5?.effectively cools the stack shell 23, and carries away the heat at arate sufficient to keep the outer shell 5I at a comparatively lowtemperature. As a result, the outer exposed surface of the latter may beprotected by a suitable coating or paint, and the unit kept in goodcondition and appearance without having to continually repaint it.

We claim:

1. The combination comprising a vertically extending closed mufflershell having a gas inlet at its lower end and an outlet at its upperend, a tube surrounding and spaced from said muffler shell and formingan inner air passage, a conduit surrounding and spaced from said tube,and forming an outer air passage, the upper ends of said air passagesbeing closed from communication, the upper end of said conduit beingopen to admit air, means connecting the lower portions of said airpassages so that the discharge of gas from the muffler outlet causes airto be drawn downwardly through said outer passage and then upwardlythrough said inner passage into the muffler discharge gas stream, and ahood connected to the upper end of said tube and comprising a gasdischarge pipe and a lower portion extending outwardly over and abovethe upper open end of said conduit.

2. The combination comprising a vertically extending closed mufflershell having a gas inlet at its lower end and an outlet at its upperend, a tube surrounding and spaced from said muffler shell and formingan inner air passage, a conduit surrounding and spaced from said tubeand forming an outer air passage, means for admitting air to said outerpassage, the upper ends of said air passages being closed fromcommunication, a foundation supporting the lower ends of said conduitand tube, an exhaust pipe extending horizontally through said conduitand tube to connect with the muffler, an air jacket surrounding Atheexhaust pipe and delivering air into said inner air passage, meansconnecting said outer passage with said air jacket and inner passage,and an outlet pipe connected to the upper end of said tube and extendingabove the muffler outlet.

3. The combination comprising a vertically extending closed mufflershell having a gas inlet at its lower end and an outlet at its upperend, a tube surrounding and spaced from said muffler shell and formingan inner air passage, a conduit surrounding and spaced from said tube,and forming an outer air passage, means for supplying air to said outerpassage, the upper ends of said air passages being closed fromcommunication, means for supplying air from said outer passage to thelower portion of said inner passage, the air being drawn into the mumerdischarge gas stream, and a hood structure connected to the upper end ofsaid tube and comprising a gas discharge pipe surrounding and extendingabove the muffler outlet, and a lower portion extending outwardly overand above the upper end of said outer passage.

4. The combination comprising a vertically extending closed mufflershell having a gas inlet at its lower end and an outlet at its upperend, a tube surrounding and spaced from said muffler shell and formingan inner air passage, a conduit surrounding and spaced from said tubeand forming an outer air passage, the upper ends of said air passagesbeing closed from communication and the upper end of said conduit beingopen to admit air, means whereby the discharge of gas from the muffleroutlet causes air to be drawn upwardly through said inner passage intothe muffler discharge gas stream, an exhaust pipe extending horizontallythrough said conin heat transferring duit and tube and connecting intothe side of the muiiler, an air jacket spacedly surrounding said exhaustpipe and extending through said conduit and tube to deliver air to saidinner air passage, and means forpassing air from said outer passagelongitudinally of said jacket and relation therewith, into the interiorof the jacket.

5. The combination comprising a vertically extending closed muiiiershell having a gas inlet at its lower end and an outlet at its upperend, a tube surrounding and spacedw from said muiiier shell and formingan inner air passage, a conduit surrounding and spaced from said tube,and forming an outer air passage, said tube and conduit being closed attheir lower ends, the upper ends of said air passages being closed fromcommunication, the upper end of said conduit being open to admit air,means connecting said air passages so that the discharge of gas from themuiier outlet causes air to be drawn downwardly through said outerpassage and then upwardly through said inner passage into the muierdischarge gas stream, an exhaust pipe extending horizontally throughsaid conduit and tube and connecting into the side of the muier, an airjacket spacedly surrounding said exhaust pipe and extending through saidconduit and tube to deliver air to said inner air passage, and means forpassing air from said outer passage longitudinally along said jacket ina direction opposite the direction of the exhaust gas flow, and intoythe jacket.

JOHN S. FLUOR, JR

PARK W. ASH.

